The present invention relates to hazardous duty garments and, more particularly, to lightweight firefighting garments that protect a wearer from extreme ambient conditions.
Protective garments are designed to shield a wearer from a variety of environmental hazards, and firefighting garments are representative of such garments. A conventional firefighting ensemble comprises a turnout coat and pant, each of which includes an outer shell, a moisture barrier located within the outer shell, a thermal liner located within the moisture barrier and an innermost face cloth layer. The outer shell typically is constructed of an abrasion-, flame- and heat-resistant material such as a woven aramid material, typically NOMEX or KEVLAR (both are trademarks of E. I. DuPont de Nemours and Co., Inc.) or a polybenzamidazole such a PBI (a trademark of Celanese Corp.) fiber material. The moisture barrier typically includes a semipermeable membrane layer which is moisture vapor permeable but impermeable to liquid moisture, such as CROSSTECH (a trademark of W. L. Gore and Associates, Inc.). The membrane layer is bonded to a substrate of high flame- and heat-resistant material, such as an aramid or PBI material.
As defined in the N.F.P.A. Standard for Protective Ensemble for Structural Firefighting, 1997 ed., the firefighting garment will include three types of seams: Major A Seams, Major B Seams and Major Seams. Major A Seams are the outer shell layer seam assemblies where a rupture of the seam could reduce protection of the garment by exposing the inner layers of the garment (such as the moisture barrier or thermal liner), the wearer""s station/work uniform, other clothing or skin. The Major A Seam must have a seam strength equal to or greater than 675 N (150 lbf). Major B Seams are moisture barrier or thermal barrier seam assemblies where a rupture of the seam could reduce protection of the garment by exposing the next inner layer of the garment, the wearer""s station/work uniform, other clothing or skin. The Major B Seam must have a seam strength equal to or greater than 337.5 N (75 lbf). Major Seams are seam assemblies not classified as Major A or Major B Seams and must have a seam strength equal to or greater than 180 N (40 lbf).
The thermal liner is typically positioned within the moisture barrier in order to prevent the thermal liner from soaking up liquid moisture flowing through the outer shell from the ambient. The thermal liner typically comprises a layer of insulation material, such as a relatively thick layer of aramid fiber batting or needlepunch, which is often quilted to a lightweight aramid fabric substrate or face cloth. The batting of the thermal barrier traps air and possesses sufficient loft to provide the necessary thermal resistance, and the fabric substrate protects the batting of the thermal liner from abrasion from the wearer.
The aforementioned components typically are arranged within the garment so that the moisture barrier layer is positioned between the thermal liner and the outer shell. This is necessary to prevent the insulating material of the thermal liner from absorbing an excessive amount of liquid moisture from the ambient, which increases the overall weight of the garment and reduces breathability of the thermal liner, thereby increasing the stress imposed by the garment on the wearer, and reduces its loft and thermal resistance characteristics. However, one disadvantage with such an arrangement is that the laminated membrane of the moisture barrier is relatively delicate and can be damaged by heat, abrasion or puncture. Such damage results in increased exposure of the thermal liner to liquid moisture, which increases liquid moisture absorption.
Another disadvantage inherent in such an arrangement is that the moisture barrier layer adds to the bulk and weight of the garment and inhibits freedom of movement of the wearer, producing a xe2x80x9chobbling effect,xe2x80x9d increasing the stress imposed on the wearer in situations requiring high activity, and accelerates the onset of fatigue. Furthermore, with such an ensemble some perspiration from the wearer is absorbed by the thermal liner. Moreover, the combination of a discrete moisture barrier and thermal liner limits breathability, especially if the thermal liner is positioned within the moisture barrier.
Additionally, many conventional firefighting garments are designed such that their thermal liner, while positioned within the moisture barrier, actually promotes the absorption of fluids, such as a firefighter""s perspiration. While such a garment may provide the firefighter short term comfort by keeping the firefighter""s skin relatively dry, in the long term, such a thermal liner will tend to lose its insulating characteristics (much like a wet pot-holder) because moisture conducts heat energy better than air.
Accordingly, there is a need for a protective garment in which the susceptibility of the thermal liner to absorption of perspiration moisture and other moisture is minimized; a protective garment which is relatively thin and lightweight, yet provides adequate thermal protection; a protective garment which is inherently able to withstand a temperature of 500xc2x0 F. for at least five minutes without igniting, melting or dripping, making it suitable for use as a firefighting garment; and a protective garment which minimizes the restriction of movement and hobbling effect characteristic of conventional firefighting garments.
The present invention is a protective garment, such as a firefighting garment, that is relatively thin and light weight. The garment possesses relatively high resistance to liquid water absorption, yet also possesses high THL (Total Heat Loss) characteristics as tested with the guarded sweating hotplate test under the N.F.P.A. (National Fire Protection Association) 1971 Standard on Protective Ensemble for Fire Fighting, 2000 edition (higher THL translates into high moisture vapor transport characteristics). The garment of the present invention includes an outer shell; a thermal liner positioned within the outer shell; a moisture barrier positioned within the thermal liner and a face cloth positioned within the moisture barrier. The thermal liner is batting, knit, spunlace, woven textile or other suitable construction of a high heat and flame resistant material (such as an aramid or PBI material, or combinations thereof) that is treated with a durable, water repellant finish to minimize liquid moisture absorption by the thermal liner. Despite the liquid moisture absorption resistance imparted onto the thermal liner by the finish, the thermal liner still retains excellent moisture vapor transport characteristics. Suitable durable, water repellant finishes may be provided by treating the thermal liner with a commercially available perfluorohydrocarbon finish, such as TEFLON (a trademark of E. I. DuPont de Nemours and Co., Inc.) and/or SCOTCHGUARD (a trademark of Minnesota Mining and Manufacturing Company). By positioning the treated thermal liner between the outer shell and the moisture barrier, the moisture barrier is protected from damage due to excessive heat from the ambient and from abrasion and wear caused by the outer shell. Additionally, by orienting the moisture barrier within the thermal barrier, the TPP (thermal protection property) of the garment is substantially increased. This allows for the reduction in the overall thickness and weight of the thermal liner throughout the garment as will be seen in the several exemplary embodiments of the invention described herein.
One exemplary embodiment of the present invention is a protective garment, such as a firefighting garment, that includes an outer shell of abrasion, flame and heat resistant material; a thermal liner positioned within the outer shell that includes at least one layer of insulating material treated with a durable, water repellant finish; a moisture barrier positioned within the thermal barrier and a face cloth positioned within the moisture barrier. The thermal barrier may consist of one or more layers of high-heat resistant batting, spunlace or knit fabric material treated with a durable, water repellant finish; and in an exemplary embodiment, the thermal barrier consists of a first layer of high-heat resistant batting, spunlace or knit fabric material quilted or laminated to a second layer of high-heat resistant batting, spunlace or knit fabric material. Either or both of the layers of insulating material may be apertured.
In another exemplary embodiment of the present invention, a protective garment, such as a firefighting garment, includes an outer shell of abrasion, flame and heat-resistant material; at least one first layer of insulating material positioned within the outer shell; a moisture barrier layer positioned within the first layer of insulating material, at least one second layer of insulating material positioned within the moisture barrier, and a face cloth positioned within the second layer of insulating material. By xe2x80x9csandwichingxe2x80x9d the moisture barrier between the at least two layers of insulating material, the total weight and/or thickness of the insulating material used throughout the garment can be substantially decreased and still meet the minimum TPP requirements of the relevant N.F.P.A. standard for firefighting garments. The first layer of insulating material is preferably a single layer of high heat- and flame-resistant woven textile material; or alternatively the first layer of insulating material may be an apertured or non-apertured spunlace, knit or batting of high heat- and flame resistant material. The second layer of insulating material is preferably a single layer of apertured high heat- and flame-resistant spunlace material; or alternatively the second layer of insulating material may be an apertured or non-apertured spunlace, knit or batting of high heat- and flame resistant material. Additionally, it is preferred that at least the first layer of insulating material is treated with a durable, water repellant finish as discussed above.
In another exemplary embodiment of the present invention, a protective garment, such as a firefighting garment, includes an outer shell of abrasion, flame and heat-resistant material, a thermal barrier/moisture barrier composite positioned between the outer shell and the wearer of the garment, where the thermal barrier/moisture barrier composite includes a substantially liquid-impermeable membrane bonded to one surface of a fabric substrate, and a first layer of insulating material attached to an opposite surface of the fabric substrate; and a thermal barrier/face cloth composite positioned between the thermal barrier/moisture barrier composite and the wearer, where the thermal barrier/face cloth composite includes a face cloth attached to a second layer of insulating material and where the face cloth faces the wearer of the garment. Preferably, the thermal barrier/moisture barrier composite is oriented such that the membrane faces the face cloth and such that the first layer of insulating material faces the outer shell. It is also preferred that the face cloth is stitched or quilted to the second layer of insulating material. Again, because of this exemplary embodiment essentially xe2x80x9csandwichesxe2x80x9d a moisture barrier between a pair of thermal barriers, the overall thickness and/or weight of the insulating materials making up the thermal barriers can be decreased. Accordingly, it is preferred that the first layer of insulating material may be a woven textile material, while the second layer of insulating material is an apertured or non-apertured spunlace, knit or batting material. Additionally, it is preferred that at least the first layer of insulating material is treated with a durable, water repellent finish.
Accordingly, it is an object of the present invention to provide a protective garment in which the thermal liner absorbs a minimal amount of liquid moisture; a protective garment in which the moisture barrier is positioned within the thermal barrier of the garment; a protective garment in which the moisture barrier is sandwiched by a pair of thermal barriers; a protective garment which reduces the amount of moisture absorbed by the thermal liner; a protect garment which is relatively thin and light weight, thereby minimizing the bulk and reducing the hobbling effect of such a garment, and also reducing material costs of the garment; and a protective garment that enhances the transport of moisture vapor there through for breathability and greater cooling (higher THL characteristics).
It is also an object of the present invention to provide a firefighting garment having an outer shell of abrasion, flame and heat resistant material, and a liner positioned within the outer shell; where the liner includes a substrate layer of high heat- and flame-resistant material bonded to a layer of substantially liquid-impermeable membrane material on one side and attached to a layer of high heat- and flame-resistant insulating material on an opposite side via a sewn and sealed Major B Seam.
It is a further object of the present invention to provide a hazardous duty garment having an outer shell of abrasion, flame and heat resistant material, and a liner positioned within the outer shell; where the liner includes a substrate layer of high heat- and flame-resistant material bonded to a layer of substantially liquid-impermeable membrane material on one side and attached to a layer of face cloth material on an opposite side via a sewn and sealed Major B Seam.
Other objects and advantages of the present invention will be apparent from the following description, the accompanying drawings and the appended claims.